Interview Questions and Answers - atozIQ

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Wednesday, 17 February 2016

Service-Oriented Architecture is an IT business system design methodology that is focused on reusability, breaking down silos, and enabling rapid and on-going optimization of business processes. An SOA can be implemented using any number of technologies. However, in practice the Web services standards and technologies (XML, SOAP, WSDL, WS-Security, WS-Policy, etc.) are at the heart of forming every organization's SOA implementation.

1. Service host factory is the mechanism by which we can create the instances of service host dynamically as the request comes in.
2. This is useful when we need to implement the event handlers for opening and closing the service.
3. WCF provides ServiceFactory class for this purpose.

WCF can create services that are similar in concept to ASMX, but it can do much more !!!
WCF is implemented on a different pipeline much more efficient than ASP.Net. It uses different serialization defaults. We can say that under the hood almost everything is different (and better)
WCF has a much better security mechanisms
WCF implement most WS* standards – Asmx Don’t. Thus WCF has security, reliability, transactions, one-way messaging and much more.
With WCF you can use any transport very easily.
As WCF is implemented on a different pipeline it does not have all Http context capabilities (Http session, cache etc)
You can host WCF on any process including a window service. It is very common.

The NetMsmqBinding is the Queued binding provided in WCF for two WCF endpoints to communicate using MSMQ. The binding therefore, exposes specific properties that are MSMQ-specific. However, not all MSMQ features and properties are exposed in the NetMsmqBinding. The NetMsmqBinding is a compact feature designed with the optimal set of features that the majority of customers would find sufficient.

WAS (Windows Activation Service) is a component of IIS 7.0. Following are few advantages :
1. We are not only limited to HTTP protocol. We can also use supported protocols like TCP, named pipes and MSMQ
2. No need to completely install IIS. We can only install WAS component and keep away the WebServer.

Transport reliability: (such as the one offered by TCP) offers point-to-point guaranteed delivery at the network packet level, as well as guarantees the order of the packets. Transport reliability is not resilient to dropping network connections and a variety of other communication problems.

Message reliability: deals with reliability at the message level independent of how many packets are required to deliver the message. Message reliability provides for end-to-end guaranteed delivery and order of messages, regardless of how many intermediaries are involved, and how many network hops are required to deliver the message from the client to the service.